DESCRIPTION: (Investigator's abstract) Analysis of living transgenic zebrafish expressing the green fluorescent protein driven by regulatory promoter sequences allows rapid identification of distant upstream specific cis-acting elements required for normal expression of developmentally essential genes. The GATA-2 gene is expressed in both hematopoietic and neuronal tissues, and has been shown to play an essential role in maintenance and proliferation of hematopoietic cells. However, the mechanisms underlying the regulation of GATA-2 gene expression and its function in the nervous system is unknown. We have generated artificial chromosome transgenic constructs that can recapitulate the endogenous expression pattern of GATA-2 in zebrafish, and have already characterized a cis-acting element required for its neuronal expression. This proposal aims to identify and characterize the genes that function to confer neuronal and hematopoietic expression of the GATA-2 gene. The outcome should make a contribution to the developmental biology of both hematopoiesis and the neurogenesis.